W 10 Creators Update Home 64-bit, avast internet security .2294, opera 44.0.2510.1449 (PGO) opens 13 seconds in sandbox, three seconds to avast forum, all while connected via VPN.
Not advisable to knock down protection shields as they would natively slow down loading of webpages.
Don't think 5 seconds is excessive; five minutes to open would point to definite issues, tho.